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Sonnanstine the Starter

After watching last night’s start, I wanted to touch on Andy Sonnanstine’s performance to date out of the rotation. With three starts under his belt, he’s racked up 15.2 innings pitched, allowed 11 hits, walked 10, struck out six, and allowed a homer. His groundball to flyball ratio is 1.00 with a BABIP of .196. He’s throwing 61% strikes with 6% whiffs. Somehow, someway, he has an ERA of 4.02. Sonnanstine’s success is solely the benefactor of fortuitous circumstance. Even with an unsustainable home run rate, Sonnanstine’s FIP is over 5.00 as a starter.

It’s evident watching him pitch that he’s not stretched out. Look, keeping up with velocities during a Sonnanstine start will always cause snark, but right now it appears he’s losing velocity – what limited velocity he has – early and often. To test this hypothesis I went to the pitchfx data and pulled each of his fastballs thrown from the starting role. Thankfully the data includes pitch count numbers and while this is hardly a perfect look at his velocity and it does not adjust for the total pitches thrown – i.e. Sonnanstine has only thrown 99 pitches once – it paints a pretty drab picture:

Your eyes aren’t lying to you, there’s a pretty clear downward moving trend. Here’s a chart with just the moving average over every five pitches:

The velocity decline itself is not unsurprising. A quick check of a handful of other Rays’ starters showed the same trend only later on in the game. What hurts the most with Sonnanstine is that he’s starting quite a few pegs beneath guys like David Price and Matt Garza. Of starting pitchers with at least 50 innings (and without outliers like Jamie Moyer and Tim Wakefield) the average fastball velocity is 90.7 MPH with a standard deviation of 2.3 MPH.

Sonnanstine’s fastball velocity is roughly 85.6 MPH as a starter – or more than two standard deviations away from the mean. The only starters who would have a lower velocity than Sonnanstine the starter (if he qualified) would be notorious coaster Livan Hernandez and R.A. Dickey, with southpaws Barry Zito and Mark Buehrle either tied or within 0.3 MPH.

I’ve always felt Sonnanstine could succeed and he has. Right now, though, I don’t think success is the most likely outcome when he takes the mound to start a game.